The invention relates to a disposable injector with a housing, in which or on which—respectively at least in certain areas—at least one mechanical spring-energy storage, at least one cylinder-piston unit which can be filled at least occasionally with active ingredient, at least one piston-actuating plunger and at least one actuating unit are arranged, wherein the spring-energy storage includes at least one pre-stressed spring element and wherein at least part of the piston-actuating plunger is positioned between the spring-energy storage and the piston of the cylinder-piston unit.
DE 36 44 984 A1 discloses inter alia such an injector which has a spring-pre-stressed piston-actuating plunger, whereof the rearward plunger rod has elastic draw hooks at its free end. The draw hooks hold the piston-actuating plunger positively firmly on one edge of the injector housing. For this they have only a minimal bearing surface on the housing. To activate the injector the draw hooks are pushed away from the edge holding them. As a result, the spring-pre-stressed piston-actuating plunger advances to complete injection.
U.S. Pat. No. 3,557,784 discloses a reusable injector, onto the housing of which a new cylinder-piston unit is inserted per use. For this purpose, the reusable injector is virtually completely disassembled and re-assembled per use. In order to hold the spring which actuates the piston-actuating plunger, two mutually opposite draw hooks are mounted on the housing of the injector via a respective mechanical pivoting joint. The two pivoting joints are arranged on the outer side of the housing.
US 2006/0129089 A1 discloses a highly complicated, multipart reusable injector. It has a tensioned piston-actuating plunger which is supported on the housing by means of a ring having a plurality of fingers. The supporting takes place with the interconnection of other, separate housing parts.
The object of the present invention is therefore to develop a modular disposable injector which has only a few components for its minimal structural size and guarantees secure mounting and function with easy handling.